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VDI: Check your expectations before moving ahead

VDI has the potential to transform the way that you manage the desktop, but there are some realities that need to be faced before you take the plunge.

Virtual desktop infrastructure is the next great frontier when it comes to virtualization.  Many, many companies have enjoyed the fruits of their labor when it coms to creating agile, available and affordable virtual infrastructures, so the next logical step would seem to be to extend these same successes to the desktop environment.

Success, however, may not be as forthcoming as one would hope.  In this article, I'll explain why you should check your expectations before moving forward with any kind of significant virtual desktop initiative.

Desktops and servers are different beasts

The first lesson is a tough one: Chuck your past.  Desktops and servers are different beasts and attempting to compare the two is an exercise in futility.  Both have vastly different performance characteristics and needs.  Most importantly, never forget this key fact: While you might be able to "bury" a performance issue with a virtual server while you order more resources to cover it, that won't happen with a virtual desktop.  A user's desktop, though, is front and center all day long.  There won't be any such thing as a "blip" that you can ignore.

VDI requires thinking about infrastructure resources a bit differently

In virtualizing servers, you're almost always going to run out of RAM before you exhaust processor and disk resources.  With VDI, you're more likely to run out of disk resources before anything else. In particular, you will more quickly hit a disk performance wall than you will a storage capacity limit.  Again, storage performance has always been important even in server virtualization, but the visibility is increased in a VDI scenario in which boot storms can take place when masses of users boot their workstations simultaneously.

So, my advice: Don't believe that your experiences with server virtualization will have fully prepared you for desktop virtualization.  Make sure that your team has done its homework so that you don't roll out a service that lands with a thud.

Licensing can be a bear

If you've done much in the way of server virtualization, you've had to learn about new ways to license your software and have had to look through the fine print in the software contracts that govern your server-based software to ensure that a virtual deployment fit the rules.  Guess what?  It only gets worse when you go to VDI.  First, you have to worry about things like Microsoft's VDA licensing.  Moreover, you have to work with individual software vendors to make sure you can deploy client software via virtual desktops.  For some inexplicable reason, some software vendors get pretty greedy when it comes to new ways to provision software, even when you have concurrent usage licenses (yes, I'm bitter!).

Advice: Never assume that any of your license agreements allow you to provision software via a virtual desktop.

WAN connectivity becomes more critical

If you're deploying virtual desktops for internal consumption only, WAN bandwidth may not be a big deal.  However, as users start to consume virtual desktops from outside the firewall, appropriate bandwidth needs to be secured in order to make sure that users have a good experience.

You're not going to save money up front

Now, for the worst news... you're not going to save money up front by going to VDI.  At best, you'll break even and will probably have to spend a bit more to do it right.  Over time, you may see some operational savings as you extend desktop equipment life cycle replacement and reduce power costs, but don't believe the "huge ROI" hype.  There is simply too much infrastructure that needs to be purchased to do it right.

That said, there may still be great reasons to do VDI, but your justification will have to be non-financial outcomes-based rather than having a direct ROI.

Summary

VDI has the potential to transform the way that you manage the desktop, but there are some realities that need to be faced before you take the plunge.  Make sure you implement for the right reasons, though.  Perhaps you need to provide desktops to remote workers or maybe you want to create an on-demand virtual computer lab for your students.  Both are worthy goals, but check your expectations before you move forward.

About

Since 1994, Scott Lowe has been providing technology solutions to a variety of organizations. After spending 10 years in multiple CIO roles, Scott is now an independent consultant, blogger, author, owner of The 1610 Group, and a Senior IT Executive w...

2 comments
Dan Cote - Virtual Computer
Dan Cote - Virtual Computer

Scott, you offer sage advice for any IT professional venturing down the VDI path to virtualize desktops. Indeed, desktops and servers are different beasts. So too are the different approaches to desktop virtualization. VDI is a server-based approach to virtualizing desktops that requires the OS, data, apps and compute power to reside in the datacenter. In this "centralize everything" model, infrastructure is the linchpin to success or failure...and the cost elephant in the room. An alternative approach is to install a type-1 hypervisor on the endpoint and centrally manage the virtualized desktops (and laptops) that operate just like a native PC. The apps stay local, making offline productivity possible and latency issues nonexistent. This client-based approach is referred to as Intelligent Desktop Virtualization (IDV), a phrase coined by Intel and used to describe Virtual Computer's NxTop product. IDV offers all the same benefits of VDI, yet it can be deployed at a fraction of the cost, and it doesn't compromise the end user experience. I'm confident that when IT professionals come to the proverbial fork in the road for their virtual desktop initiative, expectations will be exceeded if they choose the IDV path.

Gunslinger1337
Gunslinger1337

Scott has some very good points that need to be taken under consideration, and is right to warn you against those pitfalls, mainly storage. I would highly recommend that you position your infrastructure, aside from virtualization, that you start aliging your file storage with your EDRMS systems, and centralizing these stores and capabilities with your collaboration platform. Then you will be ready for VDI ;)

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